The present invention relates to an oscillating slide valve of the type provided with a slide plate, a drive device for subjecting the slide plate to an oscillating movement between a valve closing position and a valve opening position, and a mechanism for generating a sealing force in the closing position of the slide plate.
In existing oscillating slide valves, the slide plate undergoes a swinging oscillating movement resembling that of a pendulum during the acutation of the valve, which movement brings the slide plate from the opening position into the closing position, or vice versa. Furthermore, care must be taken that the slide plate, in the closed state of the valve, is pressed against the surface to be sealed so as to generate the necessary sealing force.
In known slide valves the pendulum-like movement is produced, for example, by a motor drive. The sealing force can be generated, for example, by guiding the slide plate along a plane which is inclined with respect to the sealing plane. Thus the last part of the closing movement or the first part of the opening movement, respectively, of the slide plate is not perpendicular, but rather at a relatively acute angle, to the plane at which a seal is to be produced.
This type of movement can be detrimental to the sealing effect as well as to the sealing surfaces since mutual friction cannot be avoided.
Another possible approach is to generate the sealing force, once the slide plate has stopped in its closing position, pneumatically or, for very large oscillating slide valves, by means of a second motor drive, These possibilities create technical complications and lead to a considerable increase in the cost of the oscillating slide valves.